/Engine/Plugins/Runtime/nDisplay/Source/DisplayCluster/Public/Render/Viewport/IDisplayClusterViewportManager.h
Initialize new frame for all viewports on game thread, and update context, render resources with viewport new settings And finally build render frame structure and send to render thread proxy viewport objects [Game thread func]
bool BeginNewFrame ( [FViewport](API\Runtime\Engine\FViewport) * InViewport, [UWorld](API\Runtime\Engine\Engine\UWorld) * InWorld, [FDisplayClusterRenderFrame](API\Plugins\DisplayCluster\Render\Viewport\RenderFrame\FDisplayClusterRenderFrame) & OutRenderFrame )